T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Rework bounds checking for atomic operations (#5239)

Browse Source 
Before, we would do a `heap_addr` to translate the given Wasm memory address
into a native memory address and pass it into the libcall that implemented the
atomic operation, which would then treat the address as a Wasm memory address
and pass it to `validate_atomic_addr` to be bounds checked a second time. This
is a bit nonsensical, as we are validating a native memory address as if it were
a Wasm memory address.

Now, we no longer do a `heap_addr` to translate the Wasm memory address to a
native memory address. Instead, we pass the Wasm memory address to the libcall,
and the libcall is responsible for doing the bounds check (by calling
`validate_atomic_addr` with the correct type of memory address now).
This commit is contained in:
Nick Fitzgerald
2022-11-09 16:19:43 -08:00
committed by GitHub
parent 86679489ef
commit 47fa1ad6a8
4 changed files with 74 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
crates/environ/src/builtin.rs
View File

@@ -42,11 +42,11 @@ macro_rules! foreach_builtin_function {
/// Returns an index for Wasm's `global.get` instruction for `externref`s.
externref_global_set(vmctx: vmctx, global: i32, val: reference);
/// Returns an index for wasm's `memory.atomic.notify` instruction.
memory_atomic_notify(vmctx: vmctx, memory: i32, addr: pointer, count: i32) -> i32;
memory_atomic_notify(vmctx: vmctx, memory: i32, addr: i64, count: i32) -> i32;
/// Returns an index for wasm's `memory.atomic.wait32` instruction.
memory_atomic_wait32(vmctx: vmctx, memory: i32, addr: pointer, expected: i32, timeout: i64) -> i32;
memory_atomic_wait32(vmctx: vmctx, memory: i32, addr: i64, expected: i32, timeout: i64) -> i32;
/// Returns an index for wasm's `memory.atomic.wait64` instruction.
memory_atomic_wait64(vmctx: vmctx, memory: i32, addr: pointer, expected: i64, timeout: i64) -> i32;
memory_atomic_wait64(vmctx: vmctx, memory: i32, addr: i64, expected: i64, timeout: i64) -> i32;
/// Invoked when fuel has run out while executing a function.
out_of_gas(vmctx: vmctx);
/// Invoked when we reach a new epoch.